A number of devices and fasteners are currently available for fastening panels, such as body panels and automobile interior trimpieces, to the chassis of a vehicle. As used herein, a body panel refers, for example, to any interior or exterior body panel on a vehicle, a plastic interior trimpiece or an interior trimpiece made out of any suitable material, such as wood, steel, aluminum, magnesium, carbon fiber or any other suitable material. Additionally, the panel may be any suitable exterior body panel, such as a trim piece, molding, fender, bumper, quarter panel or door panel. The chassis of the vehicle may include any substrate, plate, body panel, structural framework, chassis component or subcomponent, wall or any suitable object.
These body panels typically are required to attach to the chassis of an automobile with a relatively low level of insertion force while providing a high level of extraction force suitable to maintain attachment of the panel to the chassis. However, these conventional fastener devices instead provide approximately relatively equal levels of insertion and extraction force. Further, once the body panel is attached to the chassis via the fastener device, the fastener device is typically required to secure the panel to the chassis under a variety of environmental conditions, such as in the presence of vibration at various levels of amplitude and frequency. For example, the fastener device should prevent or minimize the amount of buzzing, rattling or any other type of noise that may cause attention to the occupants of the vehicle or otherwise weaken the attachment. Further yet, another requirement of the fastener device is that the fastener device accommodates various levels of production tolerances, such as various dimensions amongst, for example, the body panels as well as the vehicle chassis. Conventional fastener devices typically do not adequately minimize or eliminate buzzing and rattling and do not sufficiently accommodate variations in production tolerances.
Fastener clips are known for attaching body panels to an automobile chassis For example, fastener clips are known for including a base plate and four stepped arms extending from the base plate. Each stepped arm includes four incremental steps (stair-steps suitable for engaging a slot in a vehicle chassis with one of the steps on each arm. The incremental steps allow for engagement, however, in only one of the four discrete step positions rather than over a continuous range of engagement positions. Further, each step has a relatively large rise and run so that, once inserted, movement of the fastener clip within the range of a step size may occur, resulting in wear and/or the generation of noise, including buzzing and rattling as a result of vibrations occurring within the vehicle. Also, the steps typically cut onto each arm during manufacture, and also require twisting of each wing on the fastener clip in order to engage the slot in the vehicle chassis. As a result, only an edge or a portion of an edge of each of the steps engages the hole in the vehicle slot.
If the tolerances in production of the slot in the vehicle chassis or in the trimpiece exist, for example, the engagement of one portion of the hole in the chassis with one of the discrete steps on one of the arms may not provide suitable frictional engagement with another corresponding discrete step of another arm because the step size is greater than the variation of the slot height. Further, the engagement of steps of different height for different arms may not engage the slot, resulting in different levels of frictional engagement and thus causing rocking of the fastener. As a result, less than all four of the arms will make suitable engagement with the slot of the vehicle chassis. Twisting of the body panel will be likely more prevalent because less four contact points are actually made with the slot of the vehicle chassis. As a result, wear, squeaks, rattles, buzzing, corrosion and loss of elasticity and loss of sealing may result, especially after years of vehicle operation and exposure to vibration and other environmental conditions.
Fastener clips having at least two arms and a depression formed on the arms are known. For example, the depression may be formed by stamping. The depressed portions formed on each arm engage a hole in a vehicle chassis. The depressed portion formed on each arm increases an extraction force relative to an insertion force. However, when the fastener is rotated relative to the hole in the vehicle chassis, the depressed portion may lose some of its ability to maintain the high level of extraction force. For example, since each arm is typically located laterally offset from each other, each arm engages opposite sides of the hole in the vehicle chassis. Since the fastener clip only has two arms, there are only two engagement portions between the two arms and the hole in the vehicle chassis. As a result, the fastener clip may tend to rotate or pivot about the engagement portions between the arms and hole on the fastener clip, especially in response to certain forces and torques. Consequently, less than all four of the arms will make suitable engagement with the hole in the vehicle chassis. Once the fastener clip is rotated or pivoted about the engagement portion, the extraction force may be reduced.